In an image forming apparatus such as a printer, a facsimile, a copying apparatus, or the like, a sheet (e.g. a sheet of paper) is supplied to an image forming section via a conveying path from a feed tray provided at a lower portion of the image forming apparatus. The feed tray is a tray for containing a sheet to be used for image forming. Usually, the feed tray contains a standard-size sheet, which is widely used, suitable for image forming, and easy to convey.
However, a sheet used for image forming is not always the sheet contained in the feed tray. There are cases in which a special sheet is used for image forming. Examples of such a special sheet are (i) a thin sheet, (ii) a thick sheet such as a post card or the like, (iii) a colored sheet, and (iv) a sheet such as a plastic film sheet, which is made of a material different from that of a usual sheet. Such a special sheet, which is used in rare cases, is difficult to feed by using the feed tray provided inside an image forming apparatus.
Moreover, because such a special sheet is used only in rare cases, if a special sheet is always contained in the feed tray which is limited in number, the feed tray cannot be used efficiently. Therefore, before and after using special sheets, it is usually necessary to replace standard sheets contained in the feed tray with the special sheets, and vice versa. This requires a lot of time and labor. In order to overcome this drawback, many usual image forming apparatuses are provided with a feed slot outside the image forming apparatus, and a manual feed tray (i.e. a sheet conveying apparatus) for supplying a special sheet to the image forming apparatus conveniently.
Recently, image forming by an image forming apparatus is performed at an increasingly high speed. Therefore, an increasingly large number of sheets are consumed within a unit time. As a result, a usual feed tray quickly runs out of sheets. Every time a usual feed tray runs out of sheets, it is necessary to refill sheets. In many cases, therefore, an image forming apparatus is externally provided with a large-capacity sheet conveying apparatus, so as to reduce the number of sheet-refilling and save the time and labor required.
If the manual feed tray (i.e. the sheet conveying apparatus) or the large-capacity sheet conveying apparatus is provided, the image forming apparatus requires conveying paths. Through the conveying paths, the sheet is conveyed and supplied to the image forming section of a main body of the image forming apparatus. Therefore, such an image forming apparatus has a complex structure with many conveying paths. In some cases, one conveying path is provided over the other. In other cases, it is necessary to provide a very long conveying path from the sheet conveying apparatus to an inside of the main body of the image forming apparatus. In these cases, when a sheet is retained in a conveying path due to a paper jam or the like trouble, and the image forming apparatus comes to an emergency halt, it is often difficult to remove the sheet retained. It is especially difficult to remove a sheet retained in a conveying path that runs from the sheet conveying apparatus toward an inside of the image forming apparatus. For example, in order to open the conveying path, it is necessary to pull out a feed tray toward a front side of the image forming apparatus, i.e. in a direction perpendicular to a sheet conveying direction. In this case, the feed tray to be pulled out is the feed tray that is provided in a vicinity of the conveying path.
Thus, conventional image forming apparatuses have a problem that it is very difficult to remove a sheet from an opened portion if a direction of an opening of the conveying path is perpendicular to the sheet conveying direction. Moreover, if one conveying path is provided over the other, it is necessary to pull out two units, i.e. upper one and lower one, in order to open the conveying paths. This further complicates the structure of the image forming apparatus. Besides, this lowers work efficiency.
In order to solve these problems, there are proposed, for example, image forming apparatuses of Japanese Publication for Unexamined Patent Application, Tokukai 2000-16619 (publication date: Jan. 18, 2000), Japanese Publication for Unexamined Patent Application, Tokukaihei 11-322117 (publication date: Nov. 24, 1999), and the like.
Specifically, for example, the image forming apparatus of Tokukai 2000-16619 is arranged so that a large-capacity cassette (i.e. a sheet conveying apparatus) and a pair of conveying rollers are integrally pulled out in a direction opposite the sheet conveying direction. On the other hand, the image forming apparatus of Tokukaihei 11-322117 is arranged so that a manual feed tray (i.e. a sheet conveying apparatus) and a pair of registration rollers are integrally pulled out in a direction parallel to the sheet conveying direction, whereas a transferring belt is left inside the image forming apparatus.
According to these arrangements, a sufficient work space is created when a paper jam occurs. Therefore, a jammed sheet can be removed easily.
However, as described above, the image forming apparatuses of Tokukai 2000-16619 and Tokukaihei 11-322117 are arranged so that the pair of conveying rollers for conveying a sheet are pulled out integrally when the sheet conveying apparatus is pulled out. Therefore, if a sheet is jammed between the pair of conveying rollers provided to the sheet conveying apparatus, the sheet remains sandwiched between the pair of conveying rollers even after the sheet conveying apparatus is pulled out. In order to remove the sheet sandwiched between the pair of conveying rollers, the sheet needs to be pulled in the sheet conveying direction. Thus, the sheet is subjected to a stress. As a result, work efficiency is low, because the jammed sheet cannot be removed easily.